Immediately after updating my Amira to SUP 5.2, two Cfast cards I've been using for over a year are unrecognizable by the camera. I tried reformatting them using Mac Terminal with no luck. The are both Sandisk 120GB cards. Anyone else have this problem?

as replied via email, you somehow got a hold of a card version, that actually never was supported in our cameras. This is now caught by an updated filtering mechanism in SUP 5.2. I have contacted SanDisk and they will get in touch with you to get the cards replaced.

SUP 5.0 (5.0.26) does not support the larger sandisk cards. Support for the 256 Sandisk cards was added in SUP 5.2 (5.2.17). You seem have to misread the version number. If you go to https://www.arri.com/camera/amira/downloads/ you can download the current firmware 5.2 which supports those cards.